Process of making magnesia-alumina.



UNITED STATES PATENT OFFICE.

MATHEW E. ROTHBERG, OFJOHNSTOWN, PENNSYLVANIA.

PROCESS OF MAKING MAGNESlA-ALUMINA.

SPECIFICATION forming part of Letters PatentNo. 657,452, dated September 4, 1900.

Application filed November 23, 1899.

To all whom it may concern:

Be it known that I, MATHEW E. ROTHBERG, a citizen of the United States, and a resident of J ohnstown, in the county of Oambria and State of Pennsylvania, have invented certain new and useful Improvements in Processes of Manufacturing Magnesia-Alumina; and I do declare the following to be a full, clear, and

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention has relation to the manufacture of magnesia-alumina, (MgO.Al O and it consists in the novel process hereinafter set forth.

The principal materialwhich I use in carrying out this process is clay, shale, or similar material of which alumina is a constituent. The clay is treated with sulphuric acid in any of the well-known methods by which the alumina contained in it is changed to alumina sulphate, and this sulphate is leached out with water. The aqueous solution of alumina sulphate thus obtained is what I use in the first step of my process; but I may use alumina sulphate obtained in any other manner or from any other source. The aluminasulphate solution is brought into suitable tanks or vessels, and to it is added about an equal quantity of lime chloride, either dry or preferably in aqueous solution also. The admixture brings about a reaction,the resultant products of which are insoluble lime sulphate, which settles OE, and alumina chlo ride,which,being soluble,remains in the clear liquor. Fromthis alumina-chloride liquor I obtain magnesia alumina by treating it with magnesian lime either in solid form or in solution. The lime sulphate above referred to as a resultant of the reaction with lime chloride is available for the production of superior plaster-of-paris. This is effected by suitably filtering it from the clear alumina-chloride solution, washing and drying, and finally calcining it at a regulated temperature." The above described reaction between alumina sulphate and calcium chloride is usually not quite complete, a slight proportion of lime sulphate being soluble in the alumina-chlq ride liquor. Inflorder to purifythe liquorfrom the residual sulphate, after the solid lime sulphate has beenseparated I add to the Serial No. 738,071. (No specimens.)

liquor a small quantity of barium chloride, either solid or dissolved in water, in such amount as will precipitate all of the remaining sulphate in the liquor and in addition leavedissolved inthe alumina-chloride liquor a slight excess of barium chloride, which does not in terfere with the subsequent use of the liquor. On the other hand, the presence of any lime sulphate in the aluminous liquor is injurious. The barium sulphate is now filtered off and is found after suitable washing treatmentto be a very fine grade, known in the arts as precipitated baryta and extensively used. To the purified solution of alumina chloride is added magnesian quicklime, either dry or in the form of milk oflime, as may be most convenient. The reaction between the lime and the alumina chloride causes the magnesia and alumina to be precipitated from the so= lution and the lime to go into the solution in its place as lime chloride. This precipitated magnesia-alumina is found to be, after separation from the lime-chloride liquor by any common method of filtration andafter suit able washing and calcination, a very superior article for the manufacture of fire-brick. The lime-chloride liquor remaining after the separation of the magnesia-aluminais as a final step in the process returned to the tank used in the first step and is then again combined with a fresh portion of alumina sulphate for the precipitation of lime sulphate, as before. There is thus no loss of lime chloride, as it is used over and over for action of precipitation in fresh portions of alumina-sulphate liquor.

Having described this inventiomwhat I claim, and desire to secure by Letters Patent,

isl 1. The process of manufacturing magnesiaalumlna, which consists in mixing lime chloride with a solution of aluminasulphate, and subsequently adding to the alumina-chloride solution produced thereby, magnesian lime, substantially as specified.

2. The process of manufacturing magnesiaalumina, which consists in mixing lime chloride with a solutionof aluminasulphate, treating the resultantalumina-chloride solutionvwithbarium chloride, and adding to the alumina-chloride solution, so treated, magnesian lime, substantially as specified. 3. The process of manufacturing simultaneously, plaster-of-paris, alumina magne'sia, separatingthe resultant magnesia-alumina, 16 and baryta, which consists in first, mixing toandfohrthly, recovering-the lime-chloride s0- gether solutions of alumina sulphate and lution, substantially as specified.

lime chloride, and separating the resultant In testimony whereof I aflix my signature lime sulphate; secondly, treating the resuh' in presence of two witnesses.

tant alumina-chloride solution with barium y v chloride nds-eparating the resultant barium Witnesses;

MATHEW ROTHBERG.

sulphate; thirdly, adding to the purified JOHN H. BROWN alumina-chloride liquor,'inagnesian lime, and ED'W. E. LEVERGOOD. 

